scholarly journals On Estimating the Surface Wind Stress over the Sea

2018 ◽  
Vol 48 (7) ◽  
pp. 1533-1541 ◽  
Author(s):  
Larry Mahrt ◽  
Scott Miller ◽  
Tihomir Hristov ◽  
James Edson

AbstractOur study analyzes measurements primarily from two Floating Instrument Platform (FLIP) field programs and from the Air–Sea Interaction Tower (ASIT) site to examine the relationship between the wind and sea surface stress for contrasting conditions. The direct relationship of the surface momentum flux to U2 is found to be better posed than the relationship between and U, where U is the wind speed and is the friction velocity. Our datasets indicate that the stress magnitude often decreases significantly with height near the surface due to thin marine boundary layers and/or enhanced stress divergence close to the sea surface. Our study attempts to correct the surface stress estimated from traditional observational levels by using multiple observational levels near the surface and extrapolating to the surface. The effect of stability on the surface stress appears to be generally smaller than errors due to the stress divergence. Definite conclusions require more extensive measurements close to the sea surface.

2002 ◽  
Vol 124 (3) ◽  
pp. 169-172 ◽  
Author(s):  
Dag Myrhaug ◽  
Olav H. Slaattelid

The paper considers the effects of sea roughness and atmospheric stability on the sea surface wind stress over waves, which are in local equilibrium with the wind, by using the logarithmic boundary layer profile including a stability function, as well as adopting some commonly used sea surface roughness formulations. The engineering relevance of the results is also discussed.


1968 ◽  
Vol 49 (3) ◽  
pp. 247-253 ◽  
Author(s):  
E. B. Kraus

A simple sampling experiment gives a several octave range of values for the zonal surface stress obtainable from synoptic maps over the North Atlantic. Uncertainty about the value of the drag coefficient account for about half the variance. The different methods that have been used to specify this quantity are reviewed and an attempt is made to state explicitly the assumptions involved in each case.


2001 ◽  
Vol 14 (7) ◽  
pp. 1479-1498 ◽  
Author(s):  
Dudley B. Chelton ◽  
Steven K. Esbensen ◽  
Michael G. Schlax ◽  
Nicolai Thum ◽  
Michael H. Freilich ◽  
...  

2003 ◽  
Vol 16 (10) ◽  
pp. 1583-1592 ◽  
Author(s):  
A. J. Miller ◽  
S. Zhou ◽  
S-K. Yang

Abstract While several mechanisms have been suggested to account for the association of the Arctic and Antarctic Oscillations (AO/AAO) with atmospheric parameters, this paper focuses on the relationship with the atmospheric outgoing longwave radiation (OLR). The main objective of this paper is to demonstrate through AO/AAO composite analysis that the NCEP–NCAR reanalysis OLR agrees with the independent observations of the NASA Earth Radiation Budget Experiment (ERBE) broadband satellite instruments both in zonal averages and in geographically mapped space, and to verify AO/AAO characterized general circulations derived from models and analyses. The results indicate several pronounced areas of storminess that are AO/AAO dependent. One is the well-known variation over the North Atlantic Ocean toward Europe. Also, several major areas are indicated in the tropical region—one in the Indian Ocean and the others in the west and central Pacific Ocean. In addition to demonstrating that the signals are statistically significant, also tested is the relationship of the features to other well-known tropical forcing mechanisms: the Madden–Julian oscillation (MJO) and the El Niño–La Niña sea surface temperature variations. It is shown that the tropical features do, in fact, have a strong relationship to the MJO, which indicates an additional tropical–extratropical interaction. With regard to the sea surface temperature, no correlation associated with the AO/AAO variability is seen. These associations with the cloudiness and atmospheric radiation budget suggest that if there is to be improvement of numerical model forecasts to an extended time period that numerical model radiation physics will have to be taken into consideration and improved.


2020 ◽  
Author(s):  
Diego Larios ◽  
Francisco J. Ocampo-Torres ◽  
Pedro Osuna

<p>The sea surface wind stress is relevant in processes of different scales of space and time such as the exchange of gases and heat, the surface currents, the depth of the mixed layer, the turbulence injection into the ocean. The wind waves are the key component in the coupling of the lower layer of the the atmosphere and the surface layer of the ocean, and various studies have shown the direct and indirect effects on the surface wind stress. In the present study, we present the measurements of the momentum flux and the results meteorological variables at the interface between the ocean and the atmosphere, by using and Oceanographic and Marine Meteorology Buoy (BOMM1) between November 2017 and February 2018. The analysis of the results during moderate wind conditions (U<sub>10N</sub> > 8 ms<sup>-1</sup>) in which mixed sea state conditions occur (swell that interacts with locally generated wind waves) we found a decrease of the roughness length (z<sub>0</sub>), related to developing waves with higher steepness (<em>ak</em>), the data suggest that the presence of swell alters the wind sea part of the spectrum, which leads a reduction of the energy level of the wind-generated waves, hence reducing the wind sea associated roughness. For well developed waves conditions, the roughness length is greater than the parametrization proposed by Drennan <em>al</em>., (2003) for pure wind sea conditions, the data suggest that this is due direct interaction of the wind airflow and swell with higher steepness.  The data of this work suggests that during these conditions (U<sub>10N</sub> > 8 ms<sup>-1</sup>) , the mechanism of reduction of the drag of the wind sea due to the presence of swell, and the increase of the wind stress by direct interaction of swell with the airflow causes the net effect of wave field to behave as expected under pure wind sea conditions, and there seems to be no swell effect.</p>


1990 ◽  
Vol 46 (4) ◽  
pp. 177-183 ◽  
Author(s):  
Naoto Ebuchi ◽  
Yoshiaki Toba ◽  
Hiroshi Kawamura

2020 ◽  
Vol 4 (2) ◽  
pp. 129
Author(s):  
Ridwan Sala ◽  
Jafry F. Manuhutu

The presence of skipjack fish resources in a fishing area is related to the suitability of the environmental conditions of the waters. This study aims to examine the relationship of sea surface temperature (SPL) to skipjack catches and the characteristics of skipjack catches in Manokwari waters. Data, both catch data and sea surface temperature data, are collected through field surveys by following fishing operations. Furthermore, the data were analyzed descriptively using graphs and mathematically like von Bertalanffy's growth model. The results of this study found that the very small variability of SPL could not explain the variation in the volume of fishermen's catches in Manokwari waters. However, a high SST during the May - August 2013 period is thought to affect the size of the skipjack caught, where the average size of the fish caught inhabited areas near sea level. In addition, the growth of skipjack fish in Manokwari waters is relatively fast with a growth coefficient of 0.42 per year1 and natural mortality between 0.79 per year and 0.81 per year.


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